There is a great variety of revolvers and pistols employing ribs along the upper portion of the respective barrels.
Some of these ribs have a purely aesthetical purpose, but when they are correctly set, they are extremely functional in that they create a sight plan which facilitates the aiming of the pistol at the target. In some instances, these ribs are even ventilated so as to avoid aiming deformations caused by the convective movement of air when in direct contact with the heated barrel for successive firings.
In certain instances, the ribs are an integral part of the firearm as in the revolvers: Colt Python, Aminius Target, H & R - 999, Dan Wesson, S & W K 22 and the like. In other instances, they are accessories which can be adapted to certain firearms models such as BO-MAR-RIBS adapted to the Colt Mod. 1911 pistols. Lastly, there are ribs which are extremely sophisticated and which are handmade by American armorers who design revolvers specifically intended for certain types of competitions practiced almost exclusively in the United States of America.
The object of this invention is to provide a prefabricated and associated components rib adapted to be mounted on competition revolvers already constructed for precision shooting and which are thereby converted in an accurate and extremely versatile instrument with a minimum of modifications in the basic firearm, enabling the more distinct adjustments and configurations compatible with the target range practice standards.
The addition of the rib and associated components renders the resulting revolver not only ideal for the more skilled and veteran shooters, but also for aspiring champions. This is because the rib permits experimental testing of the displacement of rear sight, front sight and auxiliary weight and the effects of these modifications on shooting the firearm without the need of costly, time-consuming, irreversible and sometimes disappointing intervention of armorers which would be obligatory for conventional firearms.
The only modification required to the normal basic revolver barrel is milling the upper reinforcement thereof in a dovetail shape in order to permit the rib to be inserted and firmly attached thereto.
This rib is formed by a steel rod having a prismatic shape whose forward longer portion situated over the barrel has a generally rectangular cross-section and whose rearward shorter portion has a section in the shape of an inverted U.
Along the full upper face of the rib, there is a dovetail notch, on which the bracket for the front sight, the bracket for the rear sight and the adjustable auxiliary weight are inserted and fixed into the desired positions.
Also, in the lower face of the rib, there is a dovetail notch in register with the upper reinforcement of the barrel and into which the rib is inserted until abutting against the forward face of the revolver frame bridge. The assembly is then rendered integral by two strong Allen screws. The back portion of the rib is recessed at the bottom, and it covers the frame bridge laterally from the forward face, where the barrel is fixed, to the back portion thereof.
Mounting this heavy rib by positioning it above the barrel line either with or without the auxiliary weight, raises the center of gravity of the firearm so as to minimize its rotation upwardly as caused by the firing retraction. This is because when the firearm center of gravity is raised, this approaches the retraction line thereby reducing the respective moment and therefore the primary rotation of the revolver.
It is obvious that upon encountering reaction from the shooter's arm and hand, usually situated below the retraction line, one would have a barrel raising as a final result, but the full retraction effect is thereby attenuated. This results in a stable behavior of the revolver upon firing, without the excessive movements for raising the barrel, which are particularly inconvenient in the fast shoot modes of competition. This raised positioning of the rib rendered then the addition of auxiliary weights substantially unnecessary. However, an auxiliary weight can be still added, the total weight of the firearm remaining below the allowed limit of 1400 g, with a margin for a wider and more anatomic grasping, with a prior removal of the rear sight base, the auxiliary weight is engaged into the dovetail notch in the rib upper face and it can be attached by a respective bolt in any intermediate position from the end positions.
The sights have brackets which can slide along the dovetail slot in the rib upper face and are firmly attachable in any position deemed suitable.
In order to move the front sight bracket, a screw is loosened and the front sight can slide along the rib upper notch into which it is engaged until the desired position, wherein it will be again fixed by the screw.
The rear sight bracket can be displaced by loosening the respective Allen screw after the revolver cylinder is opened. Its displacement is limited to a maximum forwardly and to a maximum rearwardly, for which position the screw itself serves as a stop or abutment which must be fully loosened when it is desired to withdraw the sight.
In order to facilitate the mutual positioning of both front and rear sights, keeping it within the range of 220 mm, as allowed by competitive target shooting standards, two scales are engraved on the rib left side face.
The front scale is used in relation to the reference line engraved in the side of the rear sight bracket and it has its starting marking as the number 220, followed by the other markings to 5.
The other scale is found on the rib back portion and its division is also marked with number 220, followed by other markings to 5, said scale being used in relation to the reference formed by the front end of the rear sight base. These markings mean that the distance between the sights is of exactly 220 mm upon fixation of the front sight bracket corresponding to marking 220 of the front scale and the rear sight bracket corresponding to the same marking in the respective scale.
After the rear and front sights are placed in correspondance with said markings in the respective scales marked with identical numbers, the 220 mm sight base will be maintained and the sights will move backwards up to the limit indicated in FIG. 4.
It is apparent that all the intermediate positions can be obtained for sight bases smaller than 220 mm as exemplified with the firearm shooter configuration indicated by mark 197 on the rib in FIG. 2.
By means of this broad adjustment of the sight base, facilitated by the settings of the rib scales, one can meet the requirements of shooters who either prefer the more retracted position of the sights in relation to the firearm handle, and those who wish this position to be the most forward possible. Thus it is possible to meet the different tendencies in relation to the distance between the sights which is preferred to be short for some and long for others provided that it remains within the set limit of 220 mm in competition.
All the relative positions for the sights and the auxiliary weight are then possible in the rib which is the object of the present invention in order to be adapted to the individual preferences of the shooters.
The rear sight is micrometrically adjustable in height and laterally by means of a screw provided with an audible click, and it further permits the micrometric adjustment of the sight notch width for opening and closing it with a clear indication of the procedure in rear sight left face. This adjustment does not alter the lateral adjustment and is rendered a valuable instrument during the competitions when there are changes in luminosity or for adaptation to the viewing conditions for the shooter.
The front sights are easily interchangeable and they are supplied in three sizes (3,5--4,0--4,5 mm) with an additional model having colored side contrast.
The exchange of the front sights is easily made by introducing a pin into the hole existing in the upper face thereof and pressing downwardly and forwardly to release them from their fixation in the base. The front sight having colored side contrast is, as the name indicates, a classical Patridge type front sight with an acrylic insert providing a lateral contrast in deep color, without depending upon the target whiteness to permit the correct division of the sights. Thus, the shooter can keep aiming with which he is habituated even when the background is dark and therefore this front sight with side contrast is specially adapted to silhouette shooting or to those shooters who prefer aiming at the black center of the target and not at the 6 o'clock position. In both cases, the black background does not provide a contrast for the ordinary sights and emergency means with white paining on the front sight are used.
The Patridge type front sight with colored side contrast also offers a net advantage over those having colored inserts on the front sight itself, which, during competition shooting, lead to different results as a function of the illumination conditions. This is because the latter receive direct light impingement and thereby produce a glow causing low shots and when the illumination is from forward, do not produce the desired result for being seen in silhouette, which prevents the color of the insert from being perceived.
Other high visibility systems are also used by other manufacturers such as a colored spot on the front sight and a vertical bar or two spots on the rear sight, but they are more specifically adapted to night shooting. Besides not providing for the same accuracy in competition as the Patridge type sights, these systems present the same drawback of the colored insert on the front sight end when the same is seen in silhouette under normal illumination conditions of the shooting stands in which the light comes from forward.